Newbie DSLR Settings, Wide Field, No Scope

I have a Canon 1100D (EOS Rebel T3) and I also have a an intervalometer to use with it for the time lapse. So my question is, living in a Red Light area, and using the 18mm setting on the 18-55mm lens for it, what would be a good starting point for the ISO, aperture, exposure, delay settings?

I have looked through the forums and have seen a couple of other posts similar, as well as the one with a testing of settings, but nothing really definitive. I have an AC adapter to the camera, so battery life is not an issue, and since I won't be connecting it to the scope, I'm only interested in getting some wide field views of the sky.

I'm not new to either astronomy or photography, but have not really ventured into the realm of these wide night shots and would like to give it a go, so any suggestions are appreciated.

Exact settings should be tuned for your particular conditions but I can give you a few good guesses/starting points:

- For time-lapse you may actually want to shoot JPEG medium mode (however 99.9% of the time for astrophotography you will want to do RAW mode - this is about the only exception I can think of to this rule)

- Again, against all normal recommendations you may want to turn on Long Exposure Noise Reduction unless you want to do a star-trails image. (for anything *except* time-lapse you want this OFF).

- Set the ISO to 400 (I use ISO1600 on my 1000D and 350D but your 1100D has 14bit RAW so 400 may be fine)

- Set the aperture to f/5.6 (this is somewhat of a guess, but the optimum point for camera lenses is usually a couple stops down from wide open, and wide open for that lens at 18mm is f/3.5)

- Exposure time.... ok, this one is totally going to be a matter of trial and error. Try some exposure lengths to find out. Depending on light pollution levels and even how bright the stars are maximum useable exposures could be 10s or 3 minutes! Start out at 15s or 30s.

- Delay time: Does not really matter - up to you as to how you plan to do your time-lapse. I have done a couple time-lapse experiments where shot 1 image every 60s and others with shorter time periods.

Hmm... having posted that I am realizing I might have misunderstood. I assumed you are intending to make a time-lapse video out of your shots. If you are instead trying to do a wide-FOV single image the advice changes slightly:

- ISO400- Exposure the same (use camera-back histogram to judge, expose so peak is 1/3 of the way from the left edge of the graph)- Aperture to f/5.6- Delay: none (or exactly the same as your exposure time depending on how your intervalometer works)- Long Exposure Noise Reduction *OFF*- Image mode to RAW

Great starting points for reference. Thanks! I don't have (to my knowledge with a T3 anyway) the ability to turn noise reduction off or on (correct me if I'm wrong, but I don't think this camera has that ability).

This reminds me a lot of the days when I'd shoot pics of fireworks. However, that was film and the speeds were much different.

In normal deep-sky imaging both want to be entirely off as taking your own Dark frames do a better job. If you do not plan to do Dark Frame capture this time around then you can have Long Exposure Noise Reduction on instead - just keep in mind the camera will take a pause exactly as long as the exposure was at the end of each exposure. (LENR has the camera take a single internal dark-frame and auto-apply it)

I believe a red light area is where one might find women of ill repute. I'd presume you're more likely imaging from a red zone - an area with a lot of light pollution.

:-)

Just kidding - couldn't resist.

and using the 18mm setting on the 18-55mm lens for it, what would be a good starting point for the ISO, aperture, exposure, delay settings?

As far as aperture - You'll want to try some short test shots (say, 30 seconds) wide open and then stopped down one or two stops. Look at the stars in the corner and decide what is acceptable to you. The kit lens is surprisingly sharp wide open, but can usually benefit a bit by stopping down a little. You'll just have to decide the tradeoff between sharpness versus more exposure time to offset higher f/ratios.

Sean's advice is very good - set your ISO for something like 400, and then try a few snaps at various exposure lengths until you have your histogram anywhere from 15% to 50% away from the left axis (preferably closer to the lower 15%). That will be quite workable exposures assuming your polar alignment and mount are adequate for that length of exposure.

One other thing - don't be overly concerned about ISO and exposure length. There are settings that will generally work better, but you'll find that you have to be WAY out of the norm before your data won't be quite usable. Again, look at your histogram - use that as a guide and don't worry about having those settings perfect.

just keep in mind the camera will take a pause exactly as long as the exposure was at the end of each exposure. (LENR has the camera take a single internal dark-frame and auto-apply it)

Makes sense. That's what I was reading from the other posts, and the reason behind making a longer pause between each shot than the actual previous shot itself, due to the processing time of the dark frame, yes?

This internal dark frame *does* help reduce pattern noise such as hot pixels so it is better then nothing, but it also introduces a bit of extra random noise.

This is why we take many dark frames. When stacked to become a Master Dark frame the random noise component is nearly eliminated leaving only the clean pattern "noise".

So in nearly all situations it pays to simply take Dark frames. Even only 4 or 8 darks will be cleaner then the single dark of the in-camera Long Exposure Noise Reduction. LENR does have it's place - when taking single shots not intended to be stacked for example.

Honestly results from Red zone would be pretty boring. Drive just a little bit to a darker place, wait until summer Milky Way rises and you will get really spectacular images after stacking and processing. Best constellations to shoot are Cygnus and Sagittarius.Exposure at 18mm should be about 20" for Cygnus and 10" for Sagittarius.Depending on light pollution, ISO can be from 400 to 3200.

That's definitely a plan, for sure, to get to a darker site. We have a house at Anna Maria Island in the Gulf that we go to throughout the year, and besides the distant St. Petersburg lights, we can get to some dark areas around the island with the Gulf as the underdrop.

I experimented last night in my backyard and got some decent results at around 10-15 seconds at 400 ISO and f/5.6 of Orion and the Big Dipper asterism. Points were not very sharp after about 10 seconds, it seemed, and mostly the lens was racked to 18mm in the kit lens.

Thank you! I can't believe I've waited so long to get into actually doing this. I've been doing the old school SLR photography for years, just not in the work of AP. New vistas await, and I'm getting started with it at nearly 40. Lol

FYI, this article is by Jerry Lodriguss. If you liked the content in this article, you might want to know that he also has two excellent CD Books for people starting with AP. You might want to look at them:

The second book is the more "advanced" guide. Jerry has sample sections and Table of Contents on those web pages, so you can decide which book(s) may be helpful to you. I would guess that there's probably more of us that started our learning with these books than anything else.